Tropical cyclone convection: the effects of ambient vertical vorticity
Tropical cyclone convection: the effects of ambient vertical vorticity
复制标题
热带气旋对流：环境垂直涡度的影响
DOI：
10.1002/qj.819
复制
发表时间：
2011
影响因子：
8.9
通讯作者：
Roger K. Smith
中科院分区：
文献类型：
--
作者：
Ulrike Wissmeier;Roger K. Smith
我们提出了理想化的数值模式实验，以隔离和量化环境垂直涡度对深对流动力学的影响，例如在热带低压的内核区域。垂直涡量可以用均匀水平剪切、均匀固体旋转或两者的组合来表示。我们发现，不断增长的对流单体放大本地的环境旋转在低层超过一个数量级，这种涡，这是由现有的环境涡的拉伸，持续很长时间后，最初的上升气流已经衰减。显着的涡度放大发生，即使是典型的未受干扰的热带大气的背景旋转率，甚至只有中等垂直范围的云。这一发现对热带气旋的生成具有重要意义，并为热带气旋生成和热带气旋加强的统一理论提供了基础。
We present idealized numerical model experiments to isolate and quantify the influence of ambient vertical vorticity on the dynamics of deep convection, such as that in the inner‐core region of a tropical depression. The vertical vorticity is represented either by a uniform horizontal shear, a uniform solid‐body rotation, or a combination of both. We show that the growing convective cells amplify locally the ambient rotation at low levels by more than an order of magnitude and that this vorticity, which is produced by the stretching of existing ambient vorticity, persists long after the initial updraught has decayed. Significant amplification of vorticity occurs even for a background rotation rate typical of the undisturbed tropical atmosphere and even for clouds of only moderate vertical extent. This finding has important implications for tropical cyclogenesis and provides a basis for a unified theory of tropical cyclogenesis and tropical cyclone intensification.